Cartridge syringe



Oct. 19 1926.

W. H. BROCKWAY CARTRIDG sYRNGE Filed Oct. 1G, 1925 n {lavar/tor W11 EB/rwlway www Patented4 Oct. 1 9, 1926.

F I C E WILLARD H. BROCW'Y, OF NEEDHAM HEIGHTS, MASSACHUSETTS.

. CARTRIDGE SYRINGE.

Application led October 16, 1925. Serial No. 62,793.

My' present invention relatesy to improvements in cartridge type hypodermic syringes, as used in dental and surgical practice. It is its object to improve the construction of such syringes making them more effective andconvenient in operation, free from the necessity of frequent repairs, and better adapted to practical and economic manufacturing.

More particularly, my -invention involves improvements over the prior art in lsyringes of the breechloading cartridge type, in that it makes it at once possible for the surgeon or dentist to remove or separate the head or breech of the syringe, from the cylindrical holder which contains the cartridge, and 'clean' the syringe mechanism as may be necessary from time to time, as Well as to make minor repairs.

Not infrequentlythe glass cartridge, used to contain the medicament breaks at the time of the injection, causing the novocain, or serum to be spread over the spring and other internal parts of the syringe, causing annoyance and delay to the doctor and'frequently very great inconvenience to his patient. After an accident of this kind, if the syringe is not cleaned immediately, the medicament'may solidify and cause the moving parts of the syringe to stick and often to Vbecome inoperative. In emergencies requiring the use of certain drugs, time is an elcment of very great importance. With the use of the cartridge syringe, embodying my invention, delays -and annoyance now of fre-` quent occurrence will be entirely eliminated.

The economic advantages accruing from my invention, will be apparent, when it is 'pointed out that frequently when a syringe becomes stuck, or frozen, it becomes necessary to return it to thefactory to be repaired, as there has been no provision for detaching or disassembling the breech. A syringe embodying my invention makes it possible for the. surgeon or dentist to detach the breech and open it up Without tools by a' simple. manipulation of the, parts.

One of the most frequent causes of breaking of cartridges is due to the variations in the diameter of the commercial glass used in making cartridges' for containing medicament. A small cartridge may drop to one side of the cartridge holder .of the syringe, thereby getting out of line with the piston and causing the piston head to strike on the edge of the glass cartridge, instead ot' striking squarely on the rubber stopper. My.

invention provides a sufficient range to automatically center cartridges, even if they vary as much as two millimeters in diameter. Furthermore as these cartridges must be produced at a lou7 cost, the cutting to length, varies considerabl f; frequently as much as two millimeters. ily invention provides for a syringe structure, so adaptable, that variations in length as Well as in diameter are automatically cared for.

There is another important phase of my invention resultant from the principles involved. ln many uses of the hypodermic, particularly in oral Work, itis of the utmost importance that vision be obscured as little as possible and that the manipulation of the syringe be made so convenient that the operator can locate his needle point with his hand in any convenient position and yet be able by a simple extension of the thumb definitely and positively to engage the plunger handle to discharge the syringe. Une ofthe practical factors involved in such a manipulation of the syringe has beenthe undesired movement of the plunger, as for example, by'gravity, Where the syringe Was held in inverted position. lt is therefore of very great importance that the plunger be very slightly frietionally controlled Without actually interfering with the freedom of operation ofthe hypodermie.

To make this all'clear, I have shown in the accompanying drawings a form of syringe well adapted to commercial production and well received by the profession. rl'hroughout the specification and drawings like reference .characters are employed to indicate corresponding parts, and in the drawings i Fig. 1 is an elevation of a illed syringe.

Fig. 2 a fragmentary view of the same With top opened for refillment.

Fig. 3 a sectional detail of the head. Fig. 4: a View with the parts unlocked. F ig. 5 a sectional fragmentary view 0f the head.

Fig. 6 an exaggerated fragmentaryV section, and i Fig. 7 a diagrammatic illustration of the spring.

Considering, as illustrative, the construction shown, We may refer to Fig, 1 as showing one of my syringes of a generally accepted type. Generally, the construction comprises a tubular frame l having a -lower end 11, and an upper end 12. At the lower end a cap 2 is forced on by a die process vmaking a member, unaffected by heat' and having a threaded lead 21 to receive a needle 3 which may be clamped on by a c ap 4. This, with the exception of the swedged or die fitted cap is old and well adapted in our ractice. u

At the upper end my invention provides simple but very important factors. The head which constitutes a breech block for the syringe 'has usually in practice been pivotedon screws. These have proven serious factors of inconvenience. Further, the head has not been capable of dismemberment suiiicient to permit the freeing of the parts in case of 4corrosion or sticking of the plunger 9. I therefore provide. a .free and easy assemblage of parts by reasonof which all may be kept clean and clear.

Reverting to the head structure, I may describe the form shown as comprising a head cap 5 having an extension 6 and depending ears 7. These ears 7y have a pivot recess 71 and a curved lead 72. This permits the connection of the head or cap by a bayonet-like attachment and a similarly ready disconnection for cleaning or steriliz'ation.

The head 5 supports on a shoulder the finger piece 6 which is free to turn on the head below the dome 8. The dome 8 is a sleeve, die forced on the cap extension 5 so as to swage its upper edge 81 into a groove near the upper end of this member.

The plunger'stem 9 having the cross bar 11 of usual form works through the head. At its lower end it has a piston head 91 adapted to engage the cork C to expel .the charge S.

About the plunger 9 is a springlO. At its lower e'nd it bears on a block 12 through which the plunger passes. This block under the action of the spring enters the end of the frame and bears on the end of the tube T.

lThe lower vface of the block 12. is formed breech block or lock holding the head in position and the plunger in alignment, and

yat the same time holding the tube or cartridge in position.l l

To refill, the plunger is retracted until'its piston end 91 lifts the block 12 out of the frame end. The head may then be swung on the pivots 13 which are engaged in the recess 71. These pivots 13 are struck outwardly from the frame so as to providel solid rigid members on which the head may turn.

Reverting now to the spring 10 it is tobe .carefully noted that in addition to its interlocking urge'upon the breech blockv 12 it has another very important function.

Ashas been previously 'pointed out 'a hypodermic very frequently must be operated with a very considerable degree of technique, one feature of which is the finding of the handlel 11 ybythe thumb with`- out glancing from thel needle point.

The. piston head 91 is supposed to have been brought against the stopper C and the operator has gaged his thumb movement accordingly. If, however, as when the syringe is inverted, the plunger 4has dropped back, the reach to the handle 11 is lon-ger and there is lost motion in the return stroke.

By my sp-ring 10 I am able' to get a' delicate but definite control on the stem 9 in any position. I accomplish this by assembling the spring 10 under a slight compression.

That is to say before lassembling the ter-v spring fit the stem 9 as free or not under compression. The black dots are intended to indicate 1n an exaggerated way the positions of the `coils or turns -When under compression.

It will thus be lseen, that when positioned as in Fig. 3 the stem 9 is under avery slight buty definite friction. When the breech block is withdrawn to swing or remove the breech as in Fig. l, the spring 10 comes under fur- In Fig. 7 the open lines indicate the spring ther compression but at that phase the stem 9 isv wholly Withdrawn and the syringe'is not expected to be in its period of operativeV or medical use. Then ,loadedfas in Fig. 3, the spring 10 is under the proper compression to give the right friction for operative control. This function of the spring 10 is a most important feature. It happens to have the additional function of locking the breech block 12 but its control of the plunge-1' is of great importance in professional manipulation.

Thil'e the particular syringe 'shown isl one of approved commercial design it is to be understood that the features of' my invention may be otherwise embodied in whole or in part.

What I therefore claim and desire to secure by Letters Patent is:

1. In a's'yringe, a' tubular shell having an open breech at one end, and adapted to contain .a cartridge, a displaceable head normally alined with said shell, a breech block in said head, a piston slidable through said head and-breech block and adapted to urge said block into the open breech of said shell, and a trunnion bearing pivot connection between said shell and head permissive of the lll) ends adapted to frictionally engage there-` with and normally tending to enter the follower within the frame end.

3. Ina syringe of the class'described, a cartridge frame comprising a tubular shell, an integral pivot point struclroutwardly from the shell adjacent the -top thereof, a plungerhead having a pair of depending ears, each of said ears'having a ivot recess and a lead groove thereto, where y the head the frame.

4. In a syringe of the class described, a cartridge frame comprising a tubular shell, an integral pivot pointy struck outwardly from the shell adjacent the top thereof, a

plunger vhead having'a pair'of depending ears each of said ears having apivot recess v and a lead groove thereto, whereby the head may be disengaged from the frame, a follower inthe head, a piston stem passing through the follower, and a co'iled spring disposed aboutV said piston stern and having its ends adapted to frictionally engage therelower within the frame lend.

5. In a syringe, a tubula1` shell adapted to contain a cartridge, pivots on the shell adjacent the top thereof, a recessed head normally alined with said shell and having a pair of depending ears provided with pivot recesses and lead grooves thereto to said recesses adapted to receive said pivots and permitting complete detachment of the head and shell by first swinging the shell laterally on its pivots and then drawing it endwise from between said ears.

6. In a syringe of the class described, a cartridge frame comprising a tubular shell,

a pivot on the shell adjacent the top thereof,-

ufl

grap upon a plunger head having a pair of depending ears, each 'of said ears having a pivot recess and a lead groove thereto, whereby the head may be disengaged from the frame, a follower inthe head, a piston stem passing through the follower, and a coiled spring disposed about saidfpiston and having its ends adapted to frictionally engage therewith and normally tending to enter the follower within the frame end. j

l. In a syringe, a head, a plunger working through said head and a helical spring about said plunger, and compressed longitudinally within said head for frictional id plunger.

an open tending to enter the folprising a tubular shell breech, a `displaceable head, a breech block in said head and ada lted to enter the frame breech, a plunger head and block and acompression spring between said block and head and disposed to frictionally grip said plunger` when under compression. i

9. In a syringe, a recessed head, a breech bloclr therein, a plunger working through said head and a spiral spring surrounding said plunger in the head recess and bearing against said block, said spring frictionally engaging said plunger.

' v In a syringe, a plunger, ay conical helix spring normally permitting free movement of the plunger relative thereto, and means whereby the spring may be longitudinallyv compressedL to frictionally grip said plunger.

1 1. In a syringe, a cartridge frame, a recessed head pivotally mounted on the end thereof, a spring ressed breech block in said head recess and adapted to contact the cartridge end, the face of said breech block having a flaring recess to l2. In a syringe, a cartridgev frame adapted to contain a cartridge, and a springpressed follower adapted to seat against the adjacent end of a cartridge in said frame,

l said follower having a laringly recessed end effective in the seating action of the follower automatically to center the cartridge in the frame.

13. In. a syringe, a cartridge frame comhaving an open breech, pivots ony the shell adjacent the top thereof, a recessed head having a pair of depending ears provided with pivot recesses and lead grooves to said recesses adapted .to receive said pivots and permitting detachment of said frame and head by swinging the frame laterally on its pivots and followed by an endwise withdrawing Inovement, a spring pressed breech block in the recess of said head and adapted to Contact the end of a cartridge mounted in said cartridge frame, a piston stein disposed through said head and breech block, and a coil spring confined between saidbreech block and the opposite end of said head and adapted frictionally to engage said plunger when com pressed and interlockingly to urge the breech block intothe open breech of said frame.

' 14. In a syringe, a frame having an open breech, a head alined with said frame, a breech block in said head, a plunger disposed through said head and block and a single nieans for frictionally gripping the plunger' and for interloclringly seating 'the breech block in the open breech of said frame.

l5. In a syringe, a piston stem and a norinally free spiral spring conipressiblv rnisposed through said center a cartridge. v

i'ilufiowith to friclionally control the l same, and means whereby the spring may be compressed to frictionally engage it with.

the piston stem.-

16. In a syringe, a plunger, and a spring friction member normally permitting free movement of the plunger relative thereto, and means whereby the spring may be longitudinally compressed to frictionally grip said plunger.

17. In a syringe, a frame having an open breech, a head, a breech block in 'said head, a plunger Working through said head and block, a spring cooperative with said plunger and block, and compressed between said head and block to cause it to frictionally grip l15 said plunger and to interlockingly urge said breech block into the open breech of said frame.

In testimony whereof I affix my signature.

WILLARD H. BROCKWAY. 

